Gov. Phil Murphy said the U.S. Supreme Court's ruling that public workers can't be forced to contribute to labor unions amounted to a "dark day."

Murphy spoke Wednesday in Newark at an unrelated event, the same day the court dealt a serious financial blow to organized labor.

The Democratic governor, a union supporter partly propelled to the governor’s office by union workers, called the decision “disappointing.”

The court's conservative majority scrapped a 41-year-old decision that had allowed states to require that public employees pay some fees to unions that represent them, even if the workers choose not to join. The court said that mandatory union dues violated First Amendment rights.

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The 5-4 decision fulfills a longtime wish of conservatives to get rid of the so-called fair share fees.

“It’s at the essence, the core of middle class and the American dream and this undermines it,” Murphy said.

New Jersey has several powerful public sector unions including the biggest, the New Jersey Education Association, which represents teachers and school employees. The NJEA is also the most politically powerful, throwing millions into the last gubernatorial election.

The union called the decision "blatantly anti-worker" and “anti-middle class.”

President Donald Trump praised the decision and said that non-union workers are not able to support a political candidate of their choice without having union bosses decide for them.

“Big loss for the coffers of the Democrats,” the president tweeted.

Some New Jersey lawmakers called the decision a victory for taxpayers, including state Sen. Declan O’Scanlon. The Republican state senator has accused unions of driving New Jersey to have the highest taxes in the nation.

But Rutgers professor Michael Merrill says that unions will still play an important role in preserving workers’ rights.

“Unions will not disappear. Wherever there are workers gathered together, they organize. The issue is are we as a society going to recognize or force their struggles underground?” Merrill says.

Merrill says that there are many workers out there who do not have the rights that union workers have.

“There are millions of workers who are desperate for the job they have, who will swallow many an insult just to keep it, even though the employer is treating them badly,” he says.

Gov. Murphy pointed out that New Jersey enacted legislation recently to strengthen labor. Murphy signed the bill in May.

The Associated Press wire services contributed to this report.